Nov 27, 2012

National: Extremes of temperatures in the east and west.

The eastern states are about to enter a late Spring heatwave with widespread temperatures of 40 degrees expected over several days from Thursday especially in New South Wales and Queensland. This heat is due to a slow moving trough over the eastern inland and coast combining with a slow moving high in the Tasman Sea. Heat health warnings have been issued for residents in parts of eastern and south eastern Australia

At the same time cold air associated with two cold fronts circulating around a rapidly deepening low will draw cool to cold conditions across the South West Land Division of Western Australia. Widespread thundery and gusty showers and thunderstorms will develop Wednesday with small hail and cold windy conditions in the southern districts on Thursday before conditions slowly abate during Friday. Maximums in the southern districts will peak at just 16 degrees in Albany on Thursday and 20 in Perth. Severe weather warnings for damaging winds could be issued for Wednesday and Thursday.

The low and fronts will capture a trough over inland Western Australia and push it through the south east states triggering a band of thundery weather and a cooler change reaching New South Wales on Sunday. Decent rainfall with this trough looks likely to remain relatively isolated but severe thunderstorms are quite possible with the trough as it moves east.

Severe thunderstorms in New South Wales have developed again today (Tuesday) and are possible again on Wednesday especially along the ranges and slopes and into the north east but the threat then appears to ease until the trough approaches the south of the state late Friday and Saturday.